I agree it’s ideal to have all speakers equally adjusted and not boosted.
but I’m not an audiophile and kinda prefer to hear the dialogue as robustly as possible without being the only track obviously. Than be zeroed in.
Not saying I’m correct at all.
Well and nobody needs to be an audiophile to know what sounds good.
#1 is, of course, to level match all speakers. And all of us do that - if not manually, then automatically by Audyssey, YPAO, Dirac, etc.
But ONCE in a while there may be poorly mixed contents where the dialogue seems lower than the rest of the channels. And that could by temporarily fixed by either increasing the Master Volume, which obviously would also increase all other channels and could make things louder than some of us prefer, or we just temporarily increase the center dialogue channel.
I know Yamaha has a quick DIALOGUE ADJUSTMENT feature on the remote where you can increase or decrease just the center channel level. Other AVR/AVP probably have this simple dialogue adjustment feature as well.
BTW, I think both the CS9040 and CS9060 have dual 4.5 mid-woofers, while the CS9080 has dual 5.25” dual mid-woofers. So I would get the 9080, if you are going with DefTech system. Again, in general, bigger drivers + bigger cabinets = more dynamics for your dialogue.